In general, gaskets comprise a base sheet of uniform thickness which may be of metal or of a fibrous composition held together by a suitable bonding agent, and a deformable elastomer coat or bead which may cover all or only selected areas of the sheet. In use, the coat or bead deforms or spreads under pressure of forcing together the components between which the gasket material lies and provides a fluid tight seal between the parts.
At present, gaskets designed to function at high temperatures are manufactured from two or three ply laminates consisting of one or two metal sheets and one or three asbestos sheets. However, these laminates are expensive to manufacture and require excessive labor and material. Also the use of asbestos has become increasingly regarded as toxic and unsafe to handle.
U.S. Pat. No. 4,544,169 issued to David A. Cobb, et al. on Oct. 1, 1985 discloses a high temperature resistant gasket assembly including a first metallic sheet, a second metallic sheet and a wire located therebetween to surround the shape of the opening to be sealed. The wire can also be partially embedded into one of the sheets.
U.S. Pat. No. 2,289,620 issued to Wilburn F. Bernstein on July 14, 1942 discloses a cylinder head gasket comprised of a sheet of metal blanked to conform to a combustion opening, metal particles deposited on and intimately joined to the face of said gasket about the combustion openings to provide a porous roughened surface and a coating of a heat convertible synthetic resin covering and anchored to the porous surface of the metal particles to seal the space between the cylinder head and block.
The U.S. Pat. No. 3,193,920 issued to Robert D. Culberson, et al. on July 21, 1965 discloses hard metal pressure seals for electron tubes wherein the hard metal sealing rings are plated with a soft ductile metal. A soft metal gasket is placed between the two soft metal clad surfaces on each of the hard metal rings. Force is applied to the hard metal rings until the gasket yields and deforms. The gasket then adhears to the plated surfaces making a permanent sealed unit.
Normally, high temperature applications make severe demands on gaskets. Many gasket materials are simply unable to meet such demands, and those which are tentatively able to do so have quite brief useful lives.
These problems as mentioned above complicate the structures, increase cost and use toxic materials which are unsafe to handle.
The present invention is directed to overcoming one or more of the problems as set forth above.